CRITICAL FLICKER FUSION THRESHOLD AND ANTICHOLINERGIC EFFECTS OF CHRONIC ANTIDEPRESSANT TREATMENT IN REMITTED DEPRESSIVES

The persistence of deficits in cognitive performance in major depressi ve patients taking maintenance antidepressant medication was assessed by examining groups of patients in clinical remission, stable on one o f a range of tricyclics or selective serotonin re-uptake inhibitors (S SRIs) for at least 3 months, compared with controls. Measures of criti cal flicker fusion (CFF), choice reaction time (CRT), subjective sedat ion, and anticholinergic side-effect score were made. Tricyclic antide pressants (TCAs) produce a significant deficit in critical flicker fus ion threshold compared both to controls and SSRIs. Similar effects wer e seen with choice reaction times which were significantly affected by age. Sedation scores were significantly higher with TCAs than SSRIs. Anticholinergic side effects were strongly related to CFF, less so to visual analogue sedating scales and not significantly to CRT. The effe ct measured by CFF is different from sedation, and may be related to t he anticholinergic potency of the drug; it may be considered a drug-in duced pseudodementia. This effect represents a risk factor for acciden ts during maintenance therapy and may impair work and leisure performa nce. The relative risk of weight gain with TCAs compared to SSRIs in w omen was 5.92 (95% CI 1.79-19.50).